Comment 7 for bug 462949

The transparency issue is mentioned in bug #388257 as well - (see the comments 7-14) and in bug #446242. I don't know if and how the two are connected, but as Launchpad only allows to link to one bug as 'duplicate of' I decided to link to bug #388257 because it needs to be fixed first IMHO. If you are interested in the transparency issue you could subscribe yourself to bug #446242 and add a comment there if you have any further insight into what triggers the bug.